Urethane and NNK are known to be involved in the occurrence of various types of cancer.
Urethane causes lung cancer and liver cancer in mice in a dose-dependent manner. The virtually safe dose (VSD) of urethane in humans has been calculated to be 1.8×10−4 mg/kg body weight for lung cancer and 7.2×10−5 mg/kg body weight for liver cancer (K. Inai et al., Jpn. J. Cancer Res. 82, pp. 380-385, April 1991).
The offspring of pregnant mice, treated with urethane during gestation and lactation, had a significantly increased incidence of embryonic tumors, lung cancer, and ovarian cystadenomas via placental transmission, as well as endometrial hyperplasias and uterine hemangiomas in the pregnant parent mice (T. Nomura, Cancer Research, 33, pp. 1677-1683, 1973, July).
When administered per os, urethane causes lung cancer, lymphomas, hepatoma, stomach papillomas, sebaceous carcinomas, mammary tumors, squamous-cell tumors, leukemia, and mesenchymal tumors in mice (IARC MONOGRAPHS ON THE EVALUATION OF THE CARCINOGENIC RISK OF CHEMICALS TO MAN, vol. 7, pp. 111-131, the views of two IARC Working Groups on the Evaluation of the Carcinogenic Risk of Chemicals to Man which met in Lyon, 4-11 Feb. 1974 and 18-24 Jun. 1974).
Moreover, regulatory limits are implemented on urethane in Canada because urethane is produced through alcoholic fermentation and is contained at a certain level in brews such as wine (Ethyl Carbamate in Alcoholic Beverages and Fermented Foods, ACS Symposium Series No. 484, Food Safety Assessment, ed. by John W. Finley et al., pp. 419-428, published in 1992 by American Chemical Society; Identification of Volatile Constituents from Grapes, J. Agric. Food Chem., vol. 24, no. 2, pp. 329-331, 1976; RATIONALE FOR THE ESTABLISHMENT OF GUIDELINES TO LIMIT ETHYL CARBAMATE LEVELS IN ALCOHOLIC BEVERAGES, BUREAU OF CHEMICAL SAFETY, FOOD DIRECTORATE HEALTH PROTECTION BRANCH, HEALTH & WELFARE CANADA, pp. 1-8; Ethylcarbamate in Fermented Beverages and Foods, Cornelius S. Ough, J. Agric. Food Chem. vol. 24, no. 2, pp. 323-327).
NNK is a potential carcinogen present in cigarette smoke (Djordijevic, M. V. et al., A comparison of selected components in the mainstream smoke of the leading U.S. and Japanese cigarettes. In: Proceedings of the CORESTA smoke and Technology Meeting, pp. 200-217, Nov. 3-8, 1996).
Among other types of cancer, the incidence of lung cancer has continued to increase in both men and women. The occurrence of lung cancer is significantly related to smoking and alcohol consumption. The International Agency for Research on Cancer has indicated synergistic consumption of smoking and alcohols, suggesting that NNK and urethane which have been totally taken in through smoking and through intake of alcoholic beverages are a cause for lung cancer. It has been indicated that smoking directly contributes to 45% of cancer deaths in men and 21.5% in women. It appears that death from lung cancer has replaced cardiac diseases as a main cause of death among smokers in the United States.
There is a need for a dietary ingredient for preventing carcinogenesis due to smoking and alcohol intake.